The state of the art includes devices used in the domestic field to prepare ice-cream, crushed-ice fruit-drinks, "sorbets" and other similar cold products, including an ice-cream making receptacle suitable to be temporarily positioned inside a cooling chamber.
The desired ingredients are poured into the receptacle, which is cooled from outside; the ingredients are mixed and amalgamated together by a rotary whisk mounted on a shaft arranged substantially axially with respect to the receptacle.
In this type of device, since the ice-cream making receptacle can be removed, it is possible to obtain various advantages, including that of facilitating and accelerating both the collection of the ice-cream produced and the cleaning operations.
However, the fact that the ice-cream making receptacle can be removed also entails some technical problems which make the apparatus in its entirety more complex, and therefore more costly.
The state of the art includes an apparatus equipped with a a conical ice-cream making receptacle suitable to be inserted, thanks to the mating shape, into a mating conical cooling chamber defined by cooling conduits coiled substantially in a spiral.
This embodiment does not give high productivity inasmuch as it is extremely difficult to achieve a precise coupling of the cooling conduits of the cooling chamber and the removable receptacle.
The state of the art also includes an apparatus wherein the cooling chamber is defined by a receptacle suitable contain a liquid, for example brine, inside which a cooling circuit is immersed.
If on the one hand this embodiment allows to obtain great therma efficiency with repect to the previous embodiment, on the other hand it has considerable constructional complicantions apart from being very inconvenient to use.
Another disadvantage of devices known in the state of the art is that the whisks used co-operating with the aforesaid receptacles perform a satisfactory mixing of the ice-cream only in the central area of the receptacle, but they are not able to clean the bottom and inside wall.
Thus encrustations are formed which give a non-homogenous final product and limit the cooling exchange, which consequently increase the processing times.
Moreover, the mixing and amalgamation of all the ingredients is unsatisfactory.
U.S. Pat. No. 4,392,361 disclose a self-contained apparatus for making an ice cream type mixture having a mixer chamber which is cooled by a refrigerator unit and a flexible blade which is rotatably mounted in the container.
U.S. Pat. No. 4,535,604 and U.S. Pat. No. 4,573,329 disclose ice cream making machines each having an ice-cream making vassel which can be inserted in and removed from a cylindrical cooling chamber, wherein cam elements of circular from are provided for selectively enlarging the cooling chamber.
The present Applicant has designed and ambodied this invention to overcome these shortcomings and to obtain further advantages.